The present invention relates to magnetic hard disk drives. More specifically, the present invention relates to increasing the conductivity of the bonding adhesive used to adhere the slider to the suspension.
In the art today, different designs for actuator arms are utilized to improve the performance of hard disk drives. FIG. 1 provides an illustration of a typical suspension. A base plate 101 has a hole 102 through the center of the piece for coupling to the actuator arm assembly. The base plate 101 is coupled to a loadbeam 103. A suspension tongue 104 is coupled to the loadbeam 103 at the end opposite the base plate 101. The suspension tongue 104 has three suspension tongue barriers 105 for keeping the slider in position. A flexible printed circuit 106 facilitates control of the slider. Strategic holes 107 in the loadbeam 103 increase the efficiency of the actuator arm movement.
FIG. 2 provides an illustration of a suspension coupled to a slider 201. The slider 201 is coupled to the suspension tongue 104. The slider 201 is positioned over the suspension tongue barriers 105. The slider 201 is connected to the flexible printed circuit 106 by trace contact pads 202 at the trailing edge of the slider 201.
FIG. 3 provides an illustration of a cross-section of the slider 201 coupled to the suspension tongue 104. A conductive adhesive 301 couples the slider 201 to the suspension tongue 104. The conductive adhesive 301 is kept in position by the suspension barriers 105. The suspension barriers 105 are polyamide bars attached to the suspension tongue to maintain static stability of the slider in relation to the suspension tongue 104.
In a disk drive, the movement of the slider across the disk causes static charge to accumulate on the slider surface. If the static charge is not removed, the static charge will cause an electrostatic discharge that will damage the magneto-resistive element of the slider. Existing conductive adhesives, such as Eccobond C-6800J, are used in creating the slider and suspension bond to conduct the static charge from slider to suspension. The required resistance between slider and suspension becomes lower and lower as new giant magneto-resistive (GMR), tunneling magneto-resistive or next generation magnetic heads are used. The required resistance between slider and suspension can now be less than 1000 ohms. Existing conductive adhesives can only meet requirements for over 5000 ohms resistance, but cannot meet the new required resistance for GMR heads. Improvements to the conductivity of the bonding adhesive still have to meet already existing requirements of bonding strength.